media: media videobuf2: Be more flexible on the number of queue stored buffers

Add 'max_num_buffers' field in vb2_queue struct to let drivers decide
how many buffers could be stored in a queue.
This require 'bufs' array to be allocated at queue init time and freed
when releasing the queue.
By default VB2_MAX_FRAME remains the limit.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index ce5b84b9bcd45abdc3fa307ba3ec2b8122fadb46..8c1df829745b296c28eba4b7de840e44540f34b5 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -421,7 +421,7 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
  */
 static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index)
 {
-       WARN_ON(index >= VB2_MAX_FRAME || q->bufs[index] || vb->vb2_queue);
+       WARN_ON(index >= q->max_num_buffers || q->bufs[index] || vb->vb2_queue);
 
        q->bufs[index] = vb;
        vb->index = index;
@@ -454,9 +454,12 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
        struct vb2_buffer *vb;
        int ret;
 
-       /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
+       /*
+        * Ensure that the number of already queue + the number of buffers already
+        * in the queue is below q->max_num_buffers
+        */
        num_buffers = min_t(unsigned int, num_buffers,
-                           VB2_MAX_FRAME - q_num_buffers);
+                           q->max_num_buffers - q_num_buffers);
 
        for (buffer = 0; buffer < num_buffers; ++buffer) {
                /* Allocate vb2 buffer structures */
@@ -818,7 +821,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
        unsigned plane_sizes[VB2_MAX_PLANES] = { };
        bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
        unsigned int i;
-       int ret;
+       int ret = 0;
 
        if (q->streaming) {
                dprintk(q, 1, "streaming active\n");
@@ -862,17 +865,22 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
        /*
         * Make sure the requested values and current defaults are sane.
         */
-       WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
        num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
-       num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
+       num_buffers = min_t(unsigned int, num_buffers, q->max_num_buffers);
        memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
        /*
         * Set this now to ensure that drivers see the correct q->memory value
         * in the queue_setup op.
         */
        mutex_lock(&q->mmap_lock);
+       if (!q->bufs)
+               q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
+       if (!q->bufs)
+               ret = -ENOMEM;
        q->memory = memory;
        mutex_unlock(&q->mmap_lock);
+       if (ret)
+               return ret;
        set_queue_coherency(q, non_coherent_mem);
 
        /*
@@ -981,7 +989,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
        bool no_previous_buffers = !q_num_bufs;
        int ret = 0;
 
-       if (q_num_bufs == VB2_MAX_FRAME) {
+       if (q->num_buffers == q->max_num_buffers) {
                dprintk(q, 1, "maximum number of buffers already allocated\n");
                return -ENOBUFS;
        }
@@ -998,7 +1006,13 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
                 */
                mutex_lock(&q->mmap_lock);
                q->memory = memory;
+               if (!q->bufs)
+                       q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
+               if (!q->bufs)
+                       ret = -ENOMEM;
                mutex_unlock(&q->mmap_lock);
+               if (ret)
+                       return ret;
                q->waiting_for_buffers = !q->is_output;
                set_queue_coherency(q, non_coherent_mem);
        } else {
@@ -1010,7 +1024,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
                        return -EINVAL;
        }
 
-       num_buffers = min(*count, VB2_MAX_FRAME - q_num_bufs);
+       num_buffers = min(*count, q->max_num_buffers - q_num_bufs);
 
        if (requested_planes && requested_sizes) {
                num_planes = requested_planes;
@@ -2470,6 +2484,16 @@ int vb2_core_queue_init(struct vb2_queue *q)
        /*
         * Sanity check
         */
+       /*
+        * For drivers who don't support max_num_buffers ensure
+        * a backward compatibility.
+        */
+       if (!q->max_num_buffers)
+               q->max_num_buffers = VB2_MAX_FRAME;
+
+       /* The maximum is limited by offset cookie encoding pattern */
+       q->max_num_buffers = min_t(unsigned int, q->max_num_buffers, MAX_BUFFER_INDEX);
+
        if (WARN_ON(!q)                   ||
            WARN_ON(!q->ops)              ||
            WARN_ON(!q->mem_ops)          ||
@@ -2479,6 +2503,10 @@ int vb2_core_queue_init(struct vb2_queue *q)
            WARN_ON(!q->ops->buf_queue))
                return -EINVAL;
 
+       if (WARN_ON(q->max_num_buffers > MAX_BUFFER_INDEX) ||
+           WARN_ON(q->min_buffers_needed > q->max_num_buffers))
+               return -EINVAL;
+
        if (WARN_ON(q->requires_requests && !q->supports_requests))
                return -EINVAL;
 
@@ -2525,6 +2553,8 @@ void vb2_core_queue_release(struct vb2_queue *q)
        __vb2_queue_cancel(q);
        mutex_lock(&q->mmap_lock);
        __vb2_queue_free(q, vb2_get_num_buffers(q));
+       kfree(q->bufs);
+       q->bufs = NULL;
        mutex_unlock(&q->mmap_lock);
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 9d3b828cc804ba9bd40225efee1bf614acd44acd..3d71c205406d14958579a87b4f478337d57e6386 100644 (file)
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -621,7 +621,7 @@ struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp)
         * This loop doesn't scale if there is a really large number of buffers.
         * Maybe something more efficient will be needed in this case.
         */
-       for (i = 0; i < vb2_get_num_buffers(q); i++) {
+       for (i = 0; i < q->max_num_buffers; i++) {
                vb2 = vb2_get_buffer(q, i);
 
                if (!vb2)
@@ -1136,7 +1136,7 @@ int _vb2_fop_release(struct file *file, struct mutex *lock)
 
        if (lock)
                mutex_lock(lock);
-       if (file->private_data == vdev->queue->owner) {
+       if (!vdev->queue->owner || file->private_data == vdev->queue->owner) {
                vb2_queue_release(vdev->queue);
                vdev->queue->owner = NULL;
        }
@@ -1264,7 +1264,7 @@ void vb2_video_unregister_device(struct video_device *vdev)
         */
        get_device(&vdev->dev);
        video_unregister_device(vdev);
-       if (vdev->queue && vdev->queue->owner) {
+       if (vdev->queue) {
                struct mutex *lock = vdev->queue->lock ?
                        vdev->queue->lock : vdev->lock;
 

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 8f9d9e4af5b14516fadcd631768764a9b7f8a0bd..5557d78b6f20f79e4e4faa2cc1ecb12e405a4f6c 100644 (file)
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -558,6 +558,9 @@ struct vb2_buf_ops {
  * @dma_dir:   DMA mapping direction.
  * @bufs:      videobuf2 buffer structures
  * @num_buffers: number of allocated/used buffers
+ * @max_num_buffers: upper limit of number of allocated/used buffers.
+ *                  If set to 0 v4l2 core will change it VB2_MAX_FRAME
+ *                  for backward compatibility.
  * @queued_list: list of buffers currently queued from userspace
  * @queued_count: number of buffers queued and ready for streaming.
  * @owned_by_drv_count: number of buffers owned by the driver
@@ -619,8 +622,9 @@ struct vb2_queue {
        struct mutex                    mmap_lock;
        unsigned int                    memory;
        enum dma_data_direction         dma_dir;
-       struct vb2_buffer               *bufs[VB2_MAX_FRAME];
+       struct vb2_buffer               **bufs;
        unsigned int                    num_buffers;
+       unsigned int                    max_num_buffers;
 
        struct list_head                queued_list;
        unsigned int                    queued_count;
@@ -1248,6 +1252,12 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
                                                unsigned int index)
 {
+       if (!q->bufs)
+               return NULL;
+
+       if (index >= q->max_num_buffers)
+               return NULL;
+
        if (index < q->num_buffers)
                return q->bufs[index];
        return NULL;